On 2025/5/5 17:16, Christoph Hellwig wrote:
> Use writeback_iter directly instead of write_cache_pages for a nicer
> code structure and less indirect calls.
>
> Signed-off-by: Christoph Hellwig <hch@xxxxxx>
It looks clearer now.
Reviewed-by: Zhang Yi <yi.zhang@xxxxxxxxxx>
> ---
> fs/ext4/super.c | 46 ++++++++++++++++++++++------------------------
> 1 file changed, 22 insertions(+), 24 deletions(-)
>
> diff --git a/fs/ext4/super.c b/fs/ext4/super.c
> index 181934499624..6a0a3493ee43 100644
> --- a/fs/ext4/super.c
> +++ b/fs/ext4/super.c
> @@ -508,21 +508,9 @@ static void ext4_journal_commit_callback(journal_t *journal, transaction_t *txn)
> ext4_maybe_update_superblock(sb);
> }
>
> -/*
> - * This writepage callback for write_cache_pages()
> - * takes care of a few cases after page cleaning.
> - *
> - * write_cache_pages() already checks for dirty pages
> - * and calls clear_page_dirty_for_io(), which we want,
> - * to write protect the pages.
> - *
> - * However, we may have to redirty a page (see below.)
> - */
> -static int ext4_journalled_writepage_callback(struct folio *folio,
> - struct writeback_control *wbc,
> - void *data)
> +static bool ext4_journalled_writepage_needs_redirty(struct jbd2_inode *jinode,
> + struct folio *folio)
> {
> - transaction_t *transaction = (transaction_t *) data;
> struct buffer_head *bh, *head;
> struct journal_head *jh;
>
> @@ -543,15 +531,12 @@ static int ext4_journalled_writepage_callback(struct folio *folio,
> */
> jh = bh2jh(bh);
> if (buffer_dirty(bh) ||
> - (jh && (jh->b_transaction != transaction ||
> - jh->b_next_transaction))) {
> - folio_redirty_for_writepage(wbc, folio);
> - goto out;
> - }
> + (jh && (jh->b_transaction != jinode->i_transaction ||
> + jh->b_next_transaction)))
> + return true;
> } while ((bh = bh->b_this_page) != head);
>
> -out:
> - return AOP_WRITEPAGE_ACTIVATE;
> + return false;
> }
>
> static int ext4_journalled_submit_inode_data_buffers(struct jbd2_inode *jinode)
> @@ -563,10 +548,23 @@ static int ext4_journalled_submit_inode_data_buffers(struct jbd2_inode *jinode)
> .range_start = jinode->i_dirty_start,
> .range_end = jinode->i_dirty_end,
> };
> + struct folio *folio = NULL;
> + int error;
>
> - return write_cache_pages(mapping, &wbc,
> - ext4_journalled_writepage_callback,
> - jinode->i_transaction);
> + /*
> + * writeback_iter() already checks for dirty pages and calls
> + * folio_clear_dirty_for_io(), which we want to write protect the
> + * folios.
> + *
> + * However, we may have to redirty a folio sometimes.
> + */
> + while ((folio = writeback_iter(mapping, &wbc, folio, &error))) {
> + if (ext4_journalled_writepage_needs_redirty(jinode, folio))
> + folio_redirty_for_writepage(&wbc, folio);
> + folio_unlock(folio);
> + }
> +
> + return error;
> }
>
> static int ext4_journal_submit_inode_data_buffers(struct jbd2_inode *jinode)
